selinux: Use kmalloc_array() in cond_init_bool_indexes()

* A multiplication for the size determination of a memory allocation
  indicated that an array data structure should be processed.
  Thus use the corresponding function "kmalloc_array".

  This issue was detected by using the Coccinelle software.

* Replace the specification of a data type by a pointer dereference
  to make the corresponding size determination a bit safer according to
  the Linux coding style convention.
Signed-off-by: NMarkus Elfring <elfring@users.sourceforge.net>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

security/selinux/ss/conditional.c

@@ -176,8 +176,9 @@ void cond_policydb_destroy(struct policydb *p)
 int cond_init_bool_indexes(struct policydb *p)
 {
 	kfree(p->bool_val_to_struct);
-	p->bool_val_to_struct =
-		kmalloc(p->p_bools.nprim * sizeof(struct cond_bool_datum *), GFP_KERNEL);
+	p->bool_val_to_struct = kmalloc_array(p->p_bools.nprim,
+					      sizeof(*p->bool_val_to_struct),
+					      GFP_KERNEL);
 	if (!p->bool_val_to_struct)
 		return -ENOMEM;
 	return 0;